In the packing or packaging sector, plants are known which are used to make boxes by means of a plurality of workings on a packaging material, for example a sheet of cardboard.
Known plants generally comprise a plurality of operating units or stations disposed in series and provided with tools, for example cutting tools, pre-creasing tools or others.
In this type of known plant, basically the sheets progress along one or more directions of feed between the different operating units or stations, in order to be subjected at least to the traditional operations of cutting to size with respect to the development of the box, and to pre-creasing and/or cutting, in order to obtain at least the lips and the definitive preferential fold lines of the box.
Known plants also have units or stations for forming and for folding the sheet of cardboard to obtain, at the exit from the plant, a substantially finished box.
In particular, but not only, in order to make boxes intended for the industrial transport of heavy or delicate goods such as electrical appliances, electronic apparatuses, furnishing elements, mechanical components, but not only, it is known to provide that, at the end of the folding of the sheet and the definition of the box, positioning and constraining steps are provided, typically by gluing, of reinforcement elements to the formed box, which also has the function of protecting the contents against knocks.
The reinforcement elements normally consist of blocks of cardboard, wood, polystyrene or other, which are advantageously disposed at the corners and/or the internal or external edges of the box, or in any case in correspondence to the weakest parts of the box, depending on the merchandise contained therein.
The disposition and constraint of the reinforcement elements is carried out at the end of the forming steps of the box, and therefore requires an auxiliary operative intervention on a product that is, in itself, already finished, with consequent operating delays and the risk of compromising the quality of the box itself.
It is also known that, because of the complex positioning operations of the reinforcement elements inside the box, in particular in boxes with an oblong conformation or different from the characteristic parallelepiped one, the reinforcement elements are positioned by hand, with consequent possible inaccuracies and differences in positioning between one box and another.
Moreover, having to provide reinforcements, particularly along the edges and in correspondence to the corners of the box, the reinforcement elements have a complex conformation which develops on two or three Cartesian planes, therefore requiring a specific working and preparation step.
This known operating condition causes an increase in operating time and costs, as well as the need to provide complex separate operating lines for the preparation of the specific reinforcements for the box.
Document EP-A-2.000.294 shows a method to make a box which provides to attach, on a planar blank and in correspondence to four corners, a pre-formed corner element consisting of two faces or walls, converging on a common edge. This conformation can be complex to handle and position, above all having to insert the pre-formed corner element in elaborate box-like structures.
Moreover, the corner element consisting of two converging faces does not adequately protect the content of the box, in that there is always the risk that knocks on parts of the packaged product which are not in direct abutment with the faces of the corner elements can cause surface defects, markings and scratches, which lower the quality of the packaged product. This disadvantage is particularly felt in the case of high-quality and therefore high-cost packaged products, such as furnishing elements or other.
Document U.S. Pat. No. 1,791,367 describes a box-like container comprising spacer elements inside, made of corrugated cardboard, which limit the movement of the packaged products, but do not protect the perimeter of the product efficiently, the corners and sides of which can be exposed to knocks and damage.
One purpose of the present invention is to achieve a working unit and to perfect a method which allow to reduce the times and costs of making the box, in particular with regard to the positioning and constraint of the reinforcement elements.
Another purpose is to adequately protect the packaged product with the boxes which are made, in particular the corners and the overall perimeter.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.